To test water for PFAS, start with official public-water information or local health guidance, then use a certified laboratory when you need a result for your own tap or well. PFAS cannot be identified by taste, smell, clarity, common home strips, or a TDS meter.
Quick answer
- Check your water provider, state, county, or local health department first.
- Use a certified lab for PFAS results you will rely on.
- Follow the lab's sampling instructions exactly.
- Test before treatment if you need to know whether PFAS are present.
- Test after treatment if you need to confirm a system is working for your water.
- Do not use TDS, pH, hardness, chlorine strips, taste, or odor as PFAS tests.
Why PFAS testing is not a normal home test
PFAS are chemical contaminants measured at very low levels, often in parts per trillion. That is a different job from a basic home test strip.
A TDS meter can be useful for some questions about dissolved minerals and reverse osmosis performance, but it cannot identify PFAS. A glass of water can have low TDS and still require a PFAS lab test if local risk is real.
For the broader testing baseline, read How to Test Drinking Water at Home and TDS Meter Guide.
Step 1: Identify your water source
Your next step depends on whether your water comes from a public water system or a private well.
| Water source | Best first move | Why it matters |
| --- | --- | --- |
| Public water system | Check your utility, Consumer Confidence Report, state drinking-water pages, and EPA updates | Public systems may already have PFAS monitoring data or notices. |
| Private well | Contact your local health department or state well program | Private wells are usually tested by the owner, and local geology or nearby sites matter. |
| Filtered tap water | Test raw tap water first if you need source-water information | Testing only filtered water can hide whether the source has a problem. |
| After installing treatment | Test treated water when confirmation is needed | This helps verify performance for your water and maintenance condition. |
If you use public water, do not assume your own test is the only available information. EPA's public-water PFAS rule and state monitoring programs may make local information available through your utility or regulator.
Step 2: Check official information
Look for:
- Utility notices or PFAS monitoring updates.
- Your public water system's annual Consumer Confidence Report.
- State drinking-water PFAS pages.
- County or local health department guidance.
- Known PFAS sites, groundwater advisories, or private-well testing programs.
Step 3: Choose a certified lab
For PFAS decisions, use a laboratory that is certified or approved for the testing you need. CDC recommends contacting your health department for help with what to test for and how to find a state-certified lab. EPA's private-well guidance also points well owners toward certified labs and local health departments.
Before ordering the test, ask:
- Which PFAS compounds are included.
- Whether the method is appropriate for drinking water.
- What reporting limits the lab provides.
- What sample bottles and preservatives are required.
- How quickly the sample must be returned.
- Whether the lab can help interpret the result or whether you should contact a local health authority.
Step 4: Decide what to sample
The right sample point depends on the question.
| Question | Sample point |
| --- | --- |
| Does my source water have PFAS? | Untreated tap water or well water before any point-of-use filter. |
| Is my under-sink system reducing PFAS? | Treated water from the filter tap, often compared with untreated water. |
| Is my private well affected after a nearby event or advisory? | Well water at the recommended sample point from the lab or health department. |
| Is a whole-home system working? | Follow the lab or treatment professional's instructions for before-and-after sampling. |
If you are testing after treatment, keep replacement filters and service dates on hand. A result is easier to understand when you know the treatment system's age and condition.
Step 5: Read the result carefully
PFAS lab reports can include several compounds. PFOA and PFOS are two of the most familiar, but they are not the only ones.
When you receive results, look for:
- The sample date and sample location.
- The compounds tested.
- The reporting unit, usually parts per trillion or a similar very small concentration unit.
- Whether a compound was detected above the lab's reporting limit.
- Any comparison to current federal, state, or local guidance.
- Notes about sample quality or holding times.
When to test a private well for PFAS
EPA recommends annual private-well testing for total coliform bacteria, nitrates, TDS, and pH, and additional testing when other contaminants are suspected. PFAS is not covered by that basic annual list unless you specifically order it.
PFAS testing may be worth discussing with local officials if your well is near:
- A known PFAS investigation or groundwater advisory.
- A fire training area or site where firefighting foam was used.
- Certain industrial facilities.
- Landfills or waste sites with PFAS concerns.
- A location your state or county identifies as higher risk.
Testing before buying a filter
Testing before treatment helps you avoid buying the wrong system. CDC recommends choosing a filter that removes the harmful germs or chemicals you are concerned about. That means the contaminant comes first, then the filter.
If the concern is PFAS, compare your result with product claims that specifically name PFAS, total PFAS, PFOA, PFOS, or the relevant compounds. For treatment options, read Do Water Filters Remove PFAS?.
